GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello I will help you with your question,
Have you ever replaced the brake master cylinder or the power booster?
OK, I can't give you an answer with the info I have so I will opt out of your questions
Sorry I could not help
Test drive until you or whatever u have to do to get the dragging to occur, then jack up front wheels turn them if they are dragging see if it is both sides, then Crack the bleeder on caliper see if they get loose, if they do we will work on hydraulics if they don't then mechanical such as caliper to bridge or pin to bushing or piston to caliper. This is our first step